Abstract Strategic group theory has become a popular tool for analyzing competitive structure of industries. Indeed, testing for the existence of strategic groups, and the impact of strategic groups on a firm's performance, has become one of the dominant areas of empirical research in the strategic management literature. Unfortunately, the impact of this stream of research will be limited until some fundamental assertions in strategic groups theory are tested. Two of these assertions are: (1) that strategic groups exist and (2) that a firm's performance depends upon strategic group membership. These key assertions in strategic group theory remain untested for a variety of theoretical and empirical reasons. What needs to be done to test these assertions is discussed. Until these tests are complete, the contribution of the strategic groups concept will be unclear. If these tests do not build credibility for the concept of strategic groups, it may be necessary to abandon this concept and develop models where the strategically relevant attributes of firms are those that are idiosyncratic.

Strategic groups: Untested assertions and research proposals